"Electing the leader through a different mechanism is something that has to happen," he said.

Leaders of the British Labour Party, the Canadian New Democratic Party and the French Socialist Party are elected by members outside their party rooms.

New Zealand Labour recently released a report recommending a direct vote for parliamentary leader.

Dr David Burchell, from the University of Western Sydney, says the system gives little flexibility to the caucus if a leader is thought to have gone off the rails, as was the case with Mr Rudd in 2010.

"It virtually entrenches a leader who has been elected prime minister for the term of the parliament even if they go completely bananas," Dr Burchell told AAP.

He cited British Labour's election of academic Michael Foot in the 1980s and Ed Miliband in 2010 as leaders who fitted in with party ideology but did not have broad voter appeal.

Former caucus chairman Daryl Melham said "backroom factional hacks" should not determine the prime minister.

Opposition Leader Tony Abbott said the proposed changes were an admission Mr Rudd was frightened of being torn down again.

"The faceless men did it to Kevin before and he wants to make sure that he's protected against them," he said.

Labor branches in NSW, Queensland and Victoria have expressed interest in the rule change at a state level.